Communication technologies that network electronic devices are well known. Examples include: wired packet data networks; wireless packet data networks; wired telephone networks; and satellite communication networks, among other networks. These communication networks typically include a network infrastructure that services a plurality of client devices. The Public Switched Telephone Network (PSTN) is probably the best-known communication network and has been in existence for many years. The Internet, another well-known example of a communication network, has also been in existence for a number of years. Communication networks like these enable client devices to communicate with one another on a global basis.
Local Area Networks (wired LANs), e.g., Ethernets, support communications between networked computers and other devices within a serviced area. These wired LANs often link serviced devices to Wide Area Networks and the Internet. Each of these networks is generally considered a “wired” network, even though some of these networks, e.g., the PSTN, may include some transmission paths that are serviced by wireless links.
Wireless networks have come into existence more recently. Examples include cellular telephone networks, wireless LANs (WLANs), and satellite communication networks. Common forms of WLANs such as IEEE 802.11(a) networks, IEEE 802.11(b) networks, and IEEE 802.11(g) networks are referred to jointly as “IEEE 802.11 networks.” In a typical IEEE 802.11 network, a wired backbone couples to a plurality of Wireless Access Points (APs), each of which supports wireless communications with computers and other wireless terminals that include compatible wireless interfaces within a serviced area. The wired backbone couples the APs of the IEEE 802.11 network to other networks, both wired and wireless, and allows serviced wireless terminals to communicate with devices external to the IEEE 802.11 network. Devices that operate consistently with an IEEE 802.11 protocol may also support ad-hoc networking in which wireless terminals communicates directly to one another without the presence of an AP.
WLANs now also support voice communications via wireless voice terminals. In supporting the wireless voice terminals, the WLAN works in cooperation with a Private Branch Exchange (PBX) to interface the WLAN with the PSTN. A serviced call is routed between the PSTN and a serviced wireless voice terminal via the PBX and the WLAN. The wireless voice terminal may roam anywhere within the service area of the WLAN and receive voice service. However, should the wireless terminal roam outside of the service area of the WLAN, the call will be dropped. Thus, a need exists for the ability to roam with a wireless terminal that can be handed off and be serviced outside of the coverage area of the WLAN.